Modesto Police say they initially responded to a shooting on Ontario Avenue around 8:30 a.m.
A man was found in the roadway with gunshot wounds and later died at the hospital.
A description of the suspect's vehicle went out to officers, and it was spotted leaving the area.
Multiple law enforcement agencies followed the vehicle before stopping the suspect near the Sultana Drive exit.
The driver has now been taken into custody, and all lanes of Highway 99 are back open.
This is a developing story. Stay with Action News for updates.